"We filed a PIL in the High Court seeking a CBI probe or an inquiry by a member of revenue board in the multi-crore rupees scam," Srivastava and Sinha told reporters here.

Describing the alleged scam as "major one involving plunder of more than Rs 500 crore", they alleged that "rampant irregularities" had been committed in allotment of tenders for sale of country and foreign liquor by the state excise department since 2006.

Srivastava claimed that Chief Minister Nitish Kumar had gone on record saying that the dismissed excise minister Jamshed Asraf was himself involved in the scam and rejected the charge of involvement of officials in CM's secretariat in the irregularities.

"If Asraf had been involved in the irregularities of allotment of tenders for sale of liqour, then the CM should have ordered probe into the former's role but he failed to do so," he said.

"Therefore, it has become necessary to order a probe by an independent agency like CBI or member of the revenue board to unravel the truth and book the plunderers of the public money," he added.